This dinosaur, the tail has a “obsidian saw sword”

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Production: 090811 Mario

Producer: Computer Network Information Center, Chinese Academy of Sciences

Dinosaur’s weapon library is new!

I mentioned the fear of “weapons” on the dinosaurs, what would you think of? It is a “sharp teeth” of tyrannosaurus. It is Jianlong’s “Jianbao Sword”, or a “meteor hammer” …

On December 1, 2021, a study on “Nature” magazine found a new armored dinosaur

Stegouros ELENGASSEN

(Press to Take the Targe Dragon)

这只恐龙,尾巴上长了一把“黑曜石锯剑”

Its tail is inlaid with fourteen (seven pairs) large membrane bone plates, like a “

Obsidian Sky

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Tailing dragon restore diagram (Source: mauricio alvarez)

Obsidian Sky (Source: Ancient-origins.net)

See “Obsidian Sky”: An unexpected surprise

In February 2018, the ancient biologists found a Dinosaur fossil in the Río de las chinas in the south end of Chile. The formation of fossils is between (71.7 ± 1.2) million and (74.9 ± 2.1) millions of years. Since fossil exposed to the surface is only some elongated blouse bones, plus the formation has found abundant vertebrate fossil (breastfeeding animals, snake neck dragons, dragon, dinosaurs, etc.), and the ancient biologists think this is A known small dinosaury.

这只恐龙,尾巴上长了一把“黑曜石锯剑”

After that, this dinosaur fossil was excavated, gypsum, handled, and sent to the laboratory to wait for further cleanup and research. As the research launched, the rocks around the fossil were gradually knocked, this dinosaur revealed unique characteristics, completely broke the awareness of the ancient biologists – its tail end covered

Seven pairs of large membrane bone plates

However, the sheet bone is developed directly in the leather layer, also known as the intradermal ingredient. Each bone plate is flat, horizontally highlighting,

Such as the blade. This is an unprecedented tail “weapon”.

△ (a) Excavating the photo of the scene, a small amount of bone exposure; (b) is located in the pelvic and femur; (c) the bones in the cleaning, Caudal WEAPON refers to the tail weapon. (Source: Reference 1)

△ CT 3D reconstruction of the tail bones: (a-c) a total of seven-pair of membrane bone plates, the last five pairs are integrated;

(D-F) Details of the end of the end, the vertebrae after the eighteenth tail vertebrae is not stored, the author estimates that there are twenty-six. (Source: Reference 1)

In view of the “weaponization” of large membrane bones and tails, the ancient biologist judges this is a new armored dinosaury, and it is officially named

这只恐龙,尾巴上长了一把“黑曜石锯剑”

Before the hair tail dragon appeared, the tail weapon of armored dinosaur was mainly divided into two major categories: represented by Jianlong.

Tail

And representative

Huge bone hammer

. Today, the third weapon has appeared, and the ancient biologist covers the tail of seven-to-large membrane bone plate, and the image is called “macuahuitl”, that is, the ancient Aztex is used.

The 16th century waving obsidian Swords on the Aztke Sword (Source: Wikimedia Commons)

This is how to fall?

In addition to the special tail, the overall integrity of the tail dragon fossil also makes the ancient biologists feel surprised.

It is about two meters, belongs to a small armor dinosaur. That

Half of the body (tail, tibia, pelvic belt and hind limbs) remain connected, the first half of the bones are more dispersed

, Including cervical vertebrae, ventricular, forelimbs, membrane bone plates and some separate skulls.

Why can’t I keep such a high integrity?

Skeletal fossil of the tail dragon (picture source: Reference 1)

When the researcher guess, when the end of the tail dragon died, the second half of the body was buried by the slider of the river bank, and the first half of the body was exposed to the ground watch for a long time. After the devastation of nature, it was re-buried.

In addition, the death posture of the tail dragon is under the abdomen, and the hind limbs are straight, and the gentle derivation of the death in the river is the abdomen facing up, the hind limbs are bent. Researcher guess

This is because the bacterial decomposes organic matter, producing a large amount of gas causes its abdomen to expand, the expanded body is extremely unstable, easy to flip, ultimately cover the heavy back of the bone plate, and the abdomen is facing up.

Thus, we can restore this process of “obsidian saw sword”: The mid-tail dragon is likely to fall into the sand of the river, it is desperate to struggle until it is exhausted, dead, buried, become fossil …

The skeletal element of the tail dragon: The lower body is maintained, the abdomen is facing down, the lower limbs are stretched, and the upper body is broken. (Source: Reference 1)

Thanks to the highly complete bones, the study found that many bone characteristics of the tail dragon have a specific similarity to the other two of the Okada continent. The ancient biologist realized that this is only a small armored dinosaur with “obsidian saw sword”.

It is very likely to uncover the key factors of the “Mystery” of the Okaba Continent.

这只恐龙,尾巴上长了一把“黑曜石锯剑”

“Mystery” in the Okaba continent

A large number of fossil evidence shows that the Dragon Dinosaur began to evolve radiation in the Middle Jurassic, to the late Cretaceous period, its main two branches –

这只恐龙,尾巴上长了一把“黑曜石锯剑”

Organo and Tungeon

It has spread around the world and has become an important part of the ecosystem.

这只恐龙,尾巴上长了一把“黑曜石锯剑”

Although there are traces of the dragons in all mainland, the vast majority of Lauqia continent from the northern hemisphere, only a few of the Gangwana continent from the southern hemisphere, including Australia

Sensitive dragon

Minmi Paravertebra

这只恐龙,尾巴上长了一把“黑曜石锯剑”

(Quality is questioned),

Shield dragon

Kunbarrasaurus Ieversi

(The 2015 is reprinted, it was considered a new species of sensor dragons) and

Antarctica Dragon

这只恐龙,尾巴上长了一把“黑曜石锯剑”

Antarctopelta OliveRoi

All the three found in the 1980s, the remaining is some “suspected germar dragon fossil” that has not been named due to uncertainty.

Shield Dragon’s recovery map and skeletal fossil (Source: Australian Geographic; Source: Anthony O’Toole and Lucy Leahey)

In addition to the effectiveness of the suspected doubts, the scholarlong, the scholarlon, which is studying, only the San Hemispad, only left dragons and Antarctica. However, although Shield Dragon is the most complete formal dragon fossil in the Okaba continent, but it defines most of the tail and limbs. And Antarctica is just the opposite. The current only about 15% of the bones, just reserve the distal end of the tail vertebrae and the limb.

The length of the fossil is stored, so that there is a key “puzzle” between each other, it is difficult to simply take only the Dragon Evolution Relationship between the Bangwana Continent.

It can be seen that the goblin information in the South Hemisphere Okaba continent has been very scarce, and the re-relish mystery has been unveiled: whether the relationship between the Northern Hemisphere in the southern hemisphere will be more close, and represent A unique evolutionary radiation? Or the Northern Hemisphere has a more close relationship, which represents the frequent alternation of the animal group between the north and south mainland …

这只恐龙,尾巴上长了一把“黑曜石锯剑”

“Puzzle” is embedded and found new branches

Finally, the ancient biologist will be cleaned up from the rock, this important “puzzle” is born.

The study found that the common feature of the tail dragon and shield dragon exists in the humerus, pelvic, skull, and the common feature of the tail dragon and the Antarctic Dragon exists in the distal end of the limb, the tail – these fragmented clues are ingenious together, Declaring that the Okabana continent is likely to have a new bacon branch, this assumption has also been explicitly supported by system development analysis:

The tail dragon is a gentle, and the Dragon, Antarctic Dragon belongs to the same class. Their ancestors originated from 1.67 billion years ago, and I will have a new branch with other grouse, alone into new branches. Parankylosauria.

这只恐龙,尾巴上长了一把“黑曜石锯剑”

△ (a) The evolution of the Dragon family, the Shield Long appeared in 100 million years, while the tail dragon and the Antarctica dragons are similar, and the geographical position is similar, so the relationship is closer; (b) Tailing dragon and Antarctica Geographic location; (c) the tail weapon of different armored dinosaurs. (Source: Modify Self-Reference 1)

Then, the members of the parstrons (Targe Dragon, Shield Dragon, Antarctica Dragon) have other specialty compared to other legal dinosaurs?

Compared with the northern hemisphere, the limbs are thick, the armor of the army, and the southern hemisphere of the goblin (the pair of parsman) is very different, they often

Small body

Dispelling

Body side wing lacks membrane bone plate

这只恐龙,尾巴上长了一把“黑曜石锯剑”

. In addition, in addition to the special skull, many bones of the subforma have reserved the original characteristics of the flat foot (EuryPoda, the evolutionary context), which means the entire Organ family The path of the specialization starts from the beginning.

To say that the most specialty of the parstruck is inevitably a tail.

Firstly

Tail dragon

Its tail is very short, no more than twenty-six, far lower than the average of armored dinosaurs, and the last twelve tail vertebrae is surrounded by large membrane bone plates, which makes up the sharp “obsidian saw. sword”.

Antarctic

Some of the tail vertebrae is also very strange, the vertebral body is flat, there is a trench on the back, which is not common in the gel. Considering the deposition environment of Antarctica fossils is a coastal area, there is a study that these tail vertebrae belong to marine reptiles (such as snake neck dragons). However, these unique tail vertebrae also appeared in the tail dragon, combined with the zero-scattered large membrane bone plates in Antarctica dragon fossils, and the ancient biologists speculated that the end of the NAP’s tail ends also had “obsidian saws”. As for the third member

It is limited to most of the tail missing, which cannot be indirectly speculated whether it has “obsidian saw sword”.

In short, the emergence of the tail dragon not only brings the past unsolicited Dragon Evolution, but also makes the armored dinosaur family more unparalleled in land-spinal animals – this is the only independent evolution of three different Tail weapons.

Tailing dragon restore diagram (Source: Luis Perez Lopez)

This discovery has made important progress in the research of the Dragon Type Dinosaur, but is still full of unknown:

The survival age of the tail dragon and the Antarctic Dragon is about 74 million years ago, the survival age of Shield Dragon is about 100 million years ago, and the entire secondary demonstration time is 167 million years ago. Obviously, this long years still have infinite blank waiting to be filled …

So, when will the next update of the dinosaur weapon library?

references:

[1] Soto-Acuña, S., Vargas, AO, Kaluza, J. et al. Bizarre Tail WEAPONRY IN A Transitional Ankylosaur from Subantarctic Chile. Nature 600, 259-263 (2021). Https://doi.org/ 10.1038 / S41586-021-04147-1

[2] Mallon, J. C., Henderson, D. M., McDonough, C. M. & Loughry, W. A “bloatand-float” taphonomic model best explains the upside-down preservation of ankylosaurs. Palaeogeography, palaeoclimatology, palaeoecology 497, 117127 (2018).

[3] Victoria M. Arbour & Philip J. Currie (2016) Systematics, phylogeny and palaeobiogeography of the ankylosaurid dinosaurs, Journal of Systematic Palaeontology, 14: 5, 385-444, DOI: 10.1080 / 14772019.2015.1059985

[4] Leahey LG, Molnar RE, Carpenter K, Witmer LM, Salisbury SW 2015. Cranial osteology of the ankylosaurian dinosaur formerly known as Minmi sp (Ornithischia: Thyreophora).. From the Lower Cretaceous Allaru Mudstone of Richmond, Queensland, Australia. Peerj 3: E1475 https://doi.org/10.7717/peerj.1475

Stegouros ELENGASSEN

(Press to Take the Targe Dragon)

Obsidian Sky

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Shield dragon